نتایج جستجو برای: lower jurassic
تعداد نتایج: 695525 فیلتر نتایج به سال:
The holotype of the thalattosuchian Machimosaurus hugii von Meyer, 1837 from the Lower Kimmeridgian strata of Soleure, Switzerland has been erected on the basis of teeth. Due to their characteristic morphology bearing a set of pronounced vertical ridges on the enamel surface, the genus Machimosaurus von Meyer, 1837 is easily recognizable in Late Jurassic strata of Europe (Sauvage & Li nard 1879...
The Tian Shan range offers a natural laboratory to study orogenic processes. Most of the previous studies focused on either the Paleozoic evolution of the range or its Cenozoic intracontinental evolution linked with the India-Asia collision. In this study, detailed field investigations on the relationship between sedimentary cover and basement constrain the Mesozoic evolution of the northern Ti...
AB STRACT: Glauconite and Ca phosphate peloids occur in Jurassic and Cretaceous bioclastic carbonate rocks from pelagic swell sequences of the Algayat-Crevillente Unit (Subbetic Zone). The size and morphology of the peloids are controlled by the bioclasts. The glauconite in both stratigraphic positions is K rich (>0.69 atoms p.f.u.) and shows well-defined 10 AÊ lattice fringes. Poorly crystalli...
The Eskay Creek gold-silver mine, located in northwest British Columbia, is an unusually high-grade ore deposit. The mining industry continues to spend more than $2 million each year on exploration for similar deposits in the area. The geologic setting at the minesite is well studied, but large tracts in north-central British Columbia require more detailed surveys to determine if favourable sit...
The Eskay Creek gold-silver mine, located in northwest British Columbia, is the highest-grade precious-metal volcanogenic massive sulphide deposit in the world. The mining industry continues to spend more than $2 million each year on exploration for similar deposits in the area. The geologic setting at the minesite is well studied, but large tracts in north-central British Columbia require more...
The discovery of the first definitively correlated earliest Jurassic (200 million years before present) tetrapod assemblage (Fundy basin, Newark Supergroup, Nova Scotia) allows reevaluation of the duration of the Triassic-Jurassic tetrapod extinction event. Present are tritheledont and mammal-like reptiles, prosauropod, theropod, and ornithischian dinosaurs, protosuchian and sphenosuchian croco...
Quantitative subsidence analysis of 26 wells in the Lusitanian basin provides new constraints on the western Iberian Mesozoic passive margin development. Backstripped tectonic subsidence curves show a three-fold subdivision of vertical motions from Late Triassic onward. Continental rifting was initiated during the Late Triassic and Early Jurassic. From Middle Jurassic onward a distinct differen...
Following examination of the evolution of the Jurassic Andean retroarc basin at a global scale for the Central Andes, this paper analyses the pattern of the regressive process, and discusses some general features concerning Andean Jurassic Paleogeography. The early Upper Jurassic regression obeys to an exactly reverse pattern as the one evidenced for the Lower Jurassic transgressive process. Se...
Different interpretations on the timing of early diversification and radiation of modern sharks and batoids (Neoselachii) in the Earth's history exist and are related to discrepancies in taxonomic and phylogenetic interpretations favouring a Late Triassic or earliest Jurassic diversification and subsequent radiation event, respectively. Sampling standardization based on pooled taxonomic occurre...
We describe Equisetum dimorphum sp. nov. from the Lower Jurassic of Chubut Province, Patagonia, Argentina. This new species is based on fertile and vegetative remains preserved as impressions of stems, leaves, strobili, transversal sections of the stems showing their anatomy, and terminal pagoda-like structures. The fine-grained sedimentary matrix also preserved detailed impressions of epiderma...
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